Snoring is a problem suffered by a large number of people. Snoring, upper airway resistance syndrome and obstructive sleep apnea syndrome (OSAS) are all breathing disorders related to narrowing of the upper airway during sleep. Individuals over age 65 experience such sleep difficulties, and the prevalence of sleep problems will therefore increase as the over-65 population increases. Each year, sleep disorders, sleep deprivation, and excessive daytime sleepiness add billions of dollars annually to the cost of health care and in lost productivity. When the muscles at the base of the tongue and the uvula (the small fleshy tissue hanging from the center of the back of the throat) relax and sag, the relaxed tissues may vibrate as air flows past the tissues during breathing, resulting in snoring. Snoring affects about half of men and 25 percent of women—most of whom are age 50 or older.
Snoring is a common chronic medical problem that is associated with episodic partial upper airway obstruction during sleep. Snoring afflicts millions of people worldwide. Snoring can lead to chronic fatigue that follows sleep deprivation and is considered by many to be a serious medical problem. The sound of snoring is produced by turbulent air-flow moving through an area of partial upper airway obstruction that produces resonant vibrations in the soft tissues adjacent to the upper airway. In many cases, snoring is caused by the relaxation of the tongue and the resulting blockage of the breathing airway. When the tongue of the sleeping individual relaxes and creates such a blockage and the individual subsequently forcibly passes air through the breathing airway, loud vibrations between the tongue and surrounding tissues will often result in the noises commonly referred to as snoring. Snoring is created by the vibration of the pharyngeal soft tissues as air passes through an airway that is too small to allow for smooth, unimpeded flow.
A percentage of those who snore also suffer from sleep apnea. The most common type of sleep apnea, obstructive sleep apnea (OSA), is caused by repeated collapse of soft tissues forming the walls of the upper airway in the sub-glottal region during sleep. Currently accepted treatment for OSA typically includes continuous positive airway pressure (CPAP). CPAP, as currently practiced, involves connection of a pressurized air delivering device to the mouth or nose of the patient. This device typically is connected to a pressurized air source in the form of a compressor or tank with a regulator. These pressurized air supplies are expensive, large, and noisy. Because body position and sleep stages vary throughout the night, the CPAP mask pressure often does not remain constant. To address this problem, many sleep clinicians select a sufficiently high pressure setting to ensure that respiratory disturbances are reliably inhibited even in the least favorable situations. Unfortunately, this necessitates a needlessly high mask pressure for periods during which it is not required. Furthermore, the high mask pressure may make CPAP uncomfortable. Variable patient compliance remains a significant problem. Studies have found that up to 25% of patients discontinue CPAP therapy.
Airway dryness may also contribute to CPAP discomfort. The high flow rates used during CPAP may overwhelm the capacity of the nasal mucosa to heat and humidity inspired air. Compounding this problem is a phenomenon known as mouth leak. Mouth leak occurs during approximately one-third of total sleep time in people who suffer from dryness of the nose and throat. It results from the mouth being partially or fully open during nasal CPAP therapy. During mouth leak, a portion of air bypasses the nasal membranes and exits via the mouth. Normally, expiratory air releases heat and water back into the nasal mucosa by condensing on the cooled mucosal surface. Leaked air is not conditioned in this way, and results in intensification of the excessive dryness experienced during the use of CPAP. To compensate for the decreased heat and humidification caused by moth leak, blood vessels in the nose dilate; however, their capacity to do so may be overwhelmed by the high flow rates produced by CPAP. As the patient continues to mouth leak, further moisture is lost and blood vessels continue to dilate, thereby narrowing the airway. The net result of this process is increased nasal resistance and nasal congestion.
It is known that such snoring can be alleviated by displacing the individual's lower jaw into a position that is relatively forward of its normal position. A variety of known devices are designed to forwardly displace an individual's lower jaw while they are sleeping to thereby alleviate snoring. Brace-like bite splints of this type for preventing snoring serve to move the mandibula slightly forwards, since in this position of the mandibula the respiratory tracts are opened wider, enabling a person to breathe more freely without snoring. Some appliances hold the lower jaw forward during sleep while others affect tongue position. Oral appliances relieve OSAS and snoring by realigning the jaw and/or tongue in relation to the head. Oral appliance therapy, while increasingly popular to treat selected cases of sleep disordered breathing, is not completely effective in all situations.
Oral appliances can be categorized generally into three types based on design. The first type mechanically lifts the soft palate. The effectiveness of this appliance type is presumed to be due to a prevention of collapse at the velopharyngeal level. The second type positions the tongue anteriorly while the mandible retains its customary relation to the maxilla. Some oral appliances of this type use a suction cup; others are designed to work through nocturnal neuromuscular training. Most oral appliances are of the third type—mandibular advancement appliances—which, as the name implies, advance the mandible. Because the mandible is the attachment for the genioglossus and other tongue muscles, the tongue moves anteriorly, as it does with the second type. The mechanism of action of the second and third of these oral appliance designs is to enlarge the hypopharyngeal airway by moving the base of the tongue farther from contact with the posterior wall of the pharynx, thereby reducing the likelihood of collapse from inspiration.
Nasal sprays mainly work as a snoring remedy for those who suffer from nasal blockage. Snoring caused by problems with the uvula or soft palate (as most snoring problems are) are not resolved by the use of, nasal sprays or nasal passage opening devices.
U.S. Pat. No. 5,465,734 to Snorex, Inc discloses a tongue retaining device formed of a flexible polyvinyl material and hollow interior that fits over the tongue and requires a specialist to take upper and lower jaw impressions of the patient to produce a tailored device for the patient.
Numerous attempts have been made towards treating OSA and snoring. These include placing implants in either the tissue of the soft palate or the pharyngeal airway as disclosed in
U.S. Pat. No. 6,250,307 to Conrad et al. and U.S. Pat. No. 6,431,174 to Knudson et al. After implantation, tissue grows into the attachment ends and a bioresorbable member resorbs after tissue in-growth, causing tissue contraction, which results in a debulking of the tissue and movement of tissue away from opposing tissue surfaces in the pharyngeal upper airway.
Physicians often treat minor snoring by recommending that patients take simple measures such as increasing exercise, losing weight, decreasing alcohol consumption, reducing smoking, altering sleeping position, and using dental or nasal appliances. Although these relatively simple measures can be somewhat effective, many patients do not experience satisfactory relief from snoring. As a result, for many patients the only alternative is surgery.
One of the earliest surgical procedures developed, which is still in use today, is uvulopalatopharygoplasty. In addition to the poor success rates of this expensive procedure, various complications were common, including serious postoperative bleeding, pain, velopharyngeal incompetence, palatal dryness, nasopharyngeal stenosis, long-term voice changes and partial loss of taste.
Other palatal stiffening procedures, called radio frequency ablation (RFA), have been employed with mixed results, where radio frequency energy is delivered to the soft palate to cause scarring of the palatal muscle. Unfortunately, RFA must be performed multiple times to obtain satisfactory results.
In U.S. Pat. No. 5,988,171 to Sohn et al., suture material is placed around a base of the tongue and secured to the jaw, thereby moving the tissue of the base of the tongue away from the opposing tissue of the pharyngeal airway. This procedure, referred to as tongue suspension, is uncomfortable. Another technique described in U.S. Pat. No. 5,843,021 to Edwards et al., includes applying radio frequency ablation to either the tongue base or of the soft palate to debulk the tissue of the tongue or palate, respectively.
Other snoring remedies involve the injecting of a microparticle solution into a patient's soft palate to stiffen the soft palate, thereby stiffening the soft palate with the injected composition to reduce palatal flutter.
Unfortunately, all current treatments produce results that are far from optimal. Surgery and re-positioning devices are effective in only a minority of OSA patients and many people are subjected to painful and expensive procedures without benefit. While CPAP is effective in many situations, the treatment is uncomfortable and not well tolerated during long-term use. A substantial number of patients given CPAP discontinue therapy within the first year after initiation. Surgical procedures to remedy snoring are expensive, painful, and of dubious long-term benefit.
There is a long-felt but unsolved need for a simple, effective, inexpensive non-surgical method and device for treating snoring, especially one that does not rely upon uncomfortable mouth or tongue repositioners or the use of continuous positive airway pressure machines.
To date, nonsurgical approaches to the management of OSAS include behavioral modification, drug therapy, continuous positive airway pressure (CPAP), and use of mechanical devices. Behavioral modifications include avoidance of alcohol and sedative medications, alteration of sleep position, avoidance of sleep deprivation, and weight loss.